Agree. One thing I see in Pega structure is that it very tight and very difficult to understand. People have their own reasons to choose the version that best fits to their needs. Actually I'm studying for CSA 7.4 Certification and need the platform to expand my knowledge.
unfortunately pega always allow to download the latest version. but it will be really good if they keep the old version as well. it's not only for certification many project still running in old version so if we need any poc we can use the personal edition.
Only having the latest version available is not very useful for companies who are running older versions. Not to mention you are still certifying people for 7.XX versions, you should make the personal edition of those versions available for study and reference.
pega has a lot to learn from the industry -look how all the other technology vendors maintain their older versions- this is only basic - u don't even have a table of content for ur documentation -this is even below basics